CN100492845C

CN100492845C - Tri-switch single-stage voltage boosting/reducing inverter

Info

Publication number: CN100492845C
Application number: CNB2006100097549A
Authority: CN
Inventors: 谭光慧; 纪延超
Original assignee: Harbin Institute of Technology
Current assignee: Tianjin Weihan Electric Co ltd
Priority date: 2006-02-28
Filing date: 2006-02-28
Publication date: 2009-05-27
Anticipated expiration: 2026-02-28
Also published as: CN1808870A

Abstract

This invention relates to distribution generation system single buck to boost inverter, which adopts High frequency reverse interfere through main self-switch, first assistant switch tube and second assistant switch tube PWM to control its single inverter and uses basic Bick to Boost DC to DC circuit and combines two Buck t oBuck DC to DC circuits together to realize buck and boost to get new type of single inverter.

Description

A kind of tri-switch single-stage voltage boosting/reducing inverter

Technical field

The invention belongs to electrical technology field, be specifically related to a kind of single-stage voltage boosting/reducing (Buck-Boost) inverter that can be used for distributed generation system.

Background technology

Along with the increase in demand of modern society to the energy, can be fewer and feweri for primary energy such as the coal that utilizes, oil, and waste gas that the burning of power generation process coal, oil produce and refuse severe contamination natural environment has all caused very big harm to human beings'health and productive life.For fear of energy crisis, protection environment, people bring into use regenerative resource.This just makes and utilizes the distributed generation system of regenerative resource to grow up rapidly, to be used for the emergent backup of electric energy as medium and small electricity generation system, to replenish aspects such as network system, part or remote districts generating.The generation of electricity by new energy of using in the distributed generation system, the voltage that voltage, solar cell or the fuel cell that produces as variable speed wind generating produces, all can not directly be connected to the grid or power, need one-level DC-AC inverter circuit that direct current is become required alternating current to AC load.Modal DC-AC inverter circuit structure is the Buck inverter, and it is a most widely used general most important topological structure in the PWM type power conversion circuit.But because the instantaneous average output voltage of Buck inverter always forces down than input dc power, this is very restricted its application.In order to produce the output voltage higher than input voltage, need add Boost type DC-DC converter in the prime of Buck inverter, Here it is twin-stage inverter, it needs earlier input voltage DC-DC boosting inverter to be arrived certain grade, produces the output voltage higher than input direct voltage by inversion again.This just causes some problems, as strong noise, high loss, large volume, expensive and poor efficiency etc.Yet there are not the problems referred to above in single-stage inverter, it does not need the boosting inverter by DC-DC, just can in a power stage, realize boosting and inversion, and can directly obtain to be higher than the output voltage of input voltage, its compact conformation, improve conversion efficiency greatly, thereby become the preferential selection of distributed power generation inverter.Some single-stage type inverter topologies have been reported in recent years, but they or circuit structure are complicated, voltage magnitude is adjusted dumb, inversion is restive, output voltage is little, the switching tube switching loss and the switch stress that adopt are big, so be necessary to seek a kind of single-stage type inverter topology that can overcome above-mentioned shortcoming.

Summary of the invention

To adjust dumb inversion than complexity and voltage magnitude restive and output voltage is little or the switching tube switching loss and the big problem of switch stress that adopt in order to solve existing single-stage type inverter circuit structure, the invention provides a kind of tri-switch single-stage voltage boosting/reducing inverter, it is a kind of single-stage Buck-Boost inverter that is used for distributed generation system.Inverter of the present invention comprises high pass filter 2 and control circuit 5, the output of high pass filter 2 connects load or electrical network 4, described inverter also comprises main self-on-off switching tube S1, the first auxiliary self-on-off switching tube S2, the second auxiliary self-on-off switching tube S3, high frequency flyback transformer 3, resonant capacitance Cr and Power Diode Pumped D1, the cathode output end of DC power supply 1 connects the collector electrode of main self-on-off switching tube S1, the end of the same name of the primary coil L1 of the emitter connection high frequency flyback transformer 3 of main self-on-off switching tube S1 and the negative pole end of Power Diode Pumped D1, the non-same polarity of the secondary coil L2 of the positive terminal connection high frequency flyback transformer 3 of Power Diode Pumped D1 and the end of resonance capacitor C r, the end of the same name of the secondary coil L2 of high frequency flyback transformer 3 connects the emitter of the second auxiliary self-on-off switching tube S3, the non-same polarity of the primary coil L1 of high frequency flyback transformer 3 connects the collector electrode of the first auxiliary self-on-off switching tube S2, the collector electrode of the second auxiliary self-on-off switching tube S3, the emitter of the first auxiliary self-on-off switching tube S2, the other end of resonant capacitance Cr all is connected with the cathode output end of DC power supply 1, main self-on-off switching tube S1, the gate pole of the first auxiliary self-on-off switching tube S2 and the second auxiliary self-on-off switching tube S3 links to each other with three outputs of control circuit 5 respectively, and the two ends of resonant capacitance Cr are connected in parallel between two inputs of high pass filter 2.

As shown in Figure 1, the DC power supply 1 of input is by a kind of the providing in the DC power supply of solar photovoltaic power, fuel cell or variable speed wind generating generation.The primary coil L1 of high frequency flyback transformer 3 and secondary coil L2 play a part storage power and shift energy separately as the resonant inductance of Buck-Boost DC-DC converter.High pass filter 2 can make and not contain high order harmonic component in the output.When inverter connects resistive load, constituted the inverter of independent operating; And when getting access to grid, just constituted the grid type inverter.As shown in Figure 2, provided inverter SPWM modulator approach schematic diagram; In Fig. 2, be followed successively by from top to bottom: the triggering signal G3 that ac output voltage Vo or electric current I o, modulating wave Vref and carrier wave Vtri compare, the triggering signal G2 of the triggering signal G1 of main self-on-off switching tube S1, the first auxiliary self-on-off switching tube S2 and second assists self-on-off switching tube S3.In the PWM modulation, modulating wave is sinusoidal rectification pulse wave, contains two half-sinusoids in the one-period that exchanges output; Carrier wave is a sawtooth waveforms, and its frequency has determined the switching frequency of switching tube.Modulating wave and carrier wave are compared, and its intersection point has determined the angle of flow and the pulse duration of HF switch action.Provided the triggering signal of three self-on-off switchings among Fig. 2,1 expression high level (open-minded), 0 expression low level (shutoff), as seen from the figure, at the positive half wave that exchanges output, the trigger impulse of S1 and S2 is identical, the triggering signal of S3 and S1, S2 complementation, three all high frequency actions of switch; At the negative half-wave that exchanges output, S3 keeps off state always, and the gate pole of S2 is given Continuity signal always, has only S1 to move with high frequency.

There are following four kinds of mode of operations in inverter of the present invention: (a). and charge mode: in this state, S1 and S2 are open-minded, and S3 turn-offs, and DC power supply 1 is given primary coil L1 charging, and secondary coil L2 disconnects, and the input and output of inversion system do not have electrical link.All there is this pattern at the positive and negative half-wave that exchanges output.(b). the positive half wave mode of resonance: in this state, S3 is open-minded, and S1 and S2 turn-off, and the transformer energy stored passes to resonant capacitance Cr and load or electrical network 4 by secondary coil L2, constitutes resonant tank.This pattern only exists at the positive half wave that exchanges output.(c). negative half-wave mode of resonance: in this state, S2 is open-minded, and S1 and S3 turn-off.The transformer energy stored passes to resonant capacitance Cr and load or electrical network 4 by primary coil L1, constitutes resonant tank.This pattern only exists at the negative half-wave that exchanges output.(d). discharge mode: in this state, all oneself reduces to 0 to the inductive current of former limit of transformer and secondary, and S1, S2 and S3 keep off state, and resonant capacitance Cr goes up energy stored and discharges to load or electrical network 4.

The present invention is based on basic Buck-Boost DC-DC circuit, two Buck-BoostDC-DC circuit are combined, in a power stage, realize boosting and inversion, thereby obtain novel single-stage Buck-Boost inverter, it adopts high frequency flyback transformer, and the PWM by three power switchs controls and realizes the single-stage inversion.Inverter of the present invention has the following advantages: (1) its circuit structure is simple, has only used three self-turn-off devices, has reduced the volume and the cost of device; (2) it can adopt the operation of traditional control method implement device such as SPWM, and is simple and reliable, and is easy to control and implements; (3) when invertor operation in interrupted conduction mode (DCM) following time, main self-on-off switching tube and one of them auxiliary self-on-off switching tube can zero current turning-ons, realized soft switch, reduced the loss of device like this, improved the efficient of system; (4) it can be finished in a power stage and boost and inversion, and compact conformation can further improve the efficient of device; (5) owing to being operated under the higher switching frequency, so it only needs very little filter just can obtain the output current or the voltage of high-quality; (6) voltage stress of switching device is low in the inverter of the present invention, and this just means that it can select the more switching device of low capacity for use, thereby reduces the cost of whole inverter.

Description of drawings

Fig. 1 is an electrical block diagram of the present invention, and Fig. 2 is a SPWM modulation waveform schematic diagram of the present invention, abscissa express time among the figure.

Embodiment

Embodiment one: referring to Fig. 1, the inverter of this embodiment is by high pass filter 2, control circuit 5, main self-on-off switching tube S1, the first auxiliary self-on-off switching tube S2, the second auxiliary self-on-off switching tube S3, high frequency flyback transformer 3, resonant capacitance Cr and Power Diode Pumped D1 form, the cathode output end of DC power supply 1 connects the collector electrode of main self-on-off switching tube S1, the end of the same name of the primary coil L1 of the emitter connection high frequency flyback transformer 3 of main self-on-off switching tube S1 and the negative pole end of Power Diode Pumped D1, the positive terminal of Power Diode Pumped D1 connects the non-end with each end and resonance capacitor C r of the secondary coil L2 of high frequency flyback transformer 3, the end of the same name of the secondary coil L2 of high frequency flyback transformer 3 connects the emitter of the second auxiliary self-on-off switching tube S3, the non-same polarity of the primary coil L1 of high frequency flyback transformer 3 connects the collector electrode of the first auxiliary self-on-off switching tube S2, the collector electrode of the second auxiliary self-on-off switching tube S3, the emitter of the first auxiliary self-on-off switching tube S2, the other end of resonant capacitance Cr all is connected with the cathode output end of DC power supply 1, main self-on-off switching tube S1, the gate pole of the first auxiliary self-on-off switching tube S2 and the second auxiliary self-on-off switching tube S3 links to each other with three outputs of control circuit 5 respectively, the two ends of resonant capacitance Cr are connected in parallel between two inputs of high pass filter 2, and the output of high pass filter 2 connects load or electrical network 4.DC power supply 1 is provided by fuel cell; Main self-on-off switching tube S1, the first auxiliary self-on-off switching tube S2, the second auxiliary self-on-off switching tube S3 are single-way switch, and it all is IGBT, a kind of in the self-turn-off device such as GTO or MOSFET, as S1, S2, when S3 uses the switch module of the band inverse parallel diode that oneself has on the market, be connected in series a Power Diode Pumped, to guarantee the one-way of switch.

Embodiment two: referring to Fig. 1, this embodiment with the difference of embodiment one is: described high pass filter 2 contains a filter inductance Lf, the end of resonant capacitance Cr connects the end of filter inductance Lf, the other end of filter inductance Lf connects an input of load or electrical network 4, and the other end of resonant capacitance Cr links to each other with another input of load or electrical network 4.Other compositions are identical with embodiment one with annexation.

Embodiment three: referring to Fig. 1, this embodiment with the difference of embodiment two is: described high pass filter 2 also contains a filter capacitor Cf, and filter capacitor Cf is connected in parallel between two inputs of load or electrical network 4.Other compositions are identical with embodiment two with annexation.Embodiment three has been saved filter capacitor Cf than embodiment two, can alleviate the burden of filter inductance Lf like this.

Claims

1, a kind of tri-switch single-stage voltage boosting/reducing inverter, described inverter comprises high pass filter (2) and control circuit (5), the output of high pass filter (2) connects load or electrical network (4), it is characterized in that described inverter also comprises main self-on-off switching tube (S1), the first auxiliary self-on-off switching tube (S2), the second auxiliary self-on-off switching tube (S3), high frequency flyback transformer (3), resonant capacitance (Cr) and Power Diode Pumped (D1), the cathode output end of DC power supply (1) connects the collector electrode of main self-on-off switching tube (S1), the end of the same name of the primary coil (L1) of the emitter connection high frequency flyback transformer (3) of main self-on-off switching tube (S1) and the negative pole end of Power Diode Pumped (D1), the non-same polarity of the secondary coil (L2) of the positive terminal connection high frequency flyback transformer (3) of Power Diode Pumped (D1) and an end of resonant capacitance (Cr), the end of the same name of the secondary coil (L2) of high frequency flyback transformer (3) connects the emitter of the second auxiliary self-on-off switching tube (S3), the non-same polarity of the primary coil (L1) of high frequency flyback transformer (3) connects the collector electrode of the first auxiliary self-on-off switching tube (S2), the collector electrode of the second auxiliary self-on-off switching tube (S3), the emitter of the first auxiliary self-on-off switching tube (S2), the other end of resonant capacitance (Cr) all is connected with the cathode output end of DC power supply (1), main self-on-off switching tube (S1), the gate pole of the first auxiliary self-on-off switching tube (S2) and the second auxiliary self-on-off switching tube (S3) links to each other with three outputs of control circuit (5) respectively, and the two ends of resonant capacitance (Cr) are connected in parallel between two inputs of high pass filter (2).

2, a kind of tri-switch single-stage voltage boosting/reducing inverter according to claim 1 is characterized in that described DC power supply (1) is by a kind of the providing in the DC power supply of solar photovoltaic power, fuel cell or variable speed wind generating generation.

3, a kind of tri-switch single-stage voltage boosting/reducing inverter according to claim 1 is characterized in that described main self-on-off switching tube (S1), the first auxiliary self-on-off switching tube (S2), the second auxiliary self-on-off switching tube (S3) are single-way switch.

4, a kind of tri-switch single-stage voltage boosting/reducing inverter according to claim 1, it is characterized in that described high pass filter (2) contains a filter inductance (Lf), one end of resonant capacitance (Cr) connects an end of filter inductance (Lf), the other end of filter inductance (Lf) connects an input of load or electrical network (4), and the other end of resonant capacitance (Cr) links to each other with another input of load or electrical network (4).

5, a kind of tri-switch single-stage voltage boosting/reducing inverter according to claim 4 is characterized in that described high pass filter (2) also contains a filter capacitor (Cf), and filter capacitor (Cf) is connected in parallel between two inputs of load or electrical network (4).